Horazon the Summoner, delighted in summoning demons and then breaking them to his will. Horazon, along with his brother Bartuc ,were members of the Eastern mage-clan known as the Vizjerei. This mystic clan studied the ways of demons and had catalogued their lore for generations.
Empowered by this knowledge, Horazon was able to take the work of the Vizjerei and pervert it for his demented purposes. The denizens of Hell sought revenge against this bold mortal, but Horazon managed to keep himself well protected within his arcane sanctuary.
Source
- Diablo I Manual, page 62